I have tried adding PHC to the configuration of chrony and see things
MS Name/IP address Stratum Poll Reach LastRx Last sample
#x PHC0 0 3 377 11 -322ms[ -322ms]
^* ntp-clock-1 1 4 377 11 -2579ns[-4000ns] +/-
^- ntp-clock-2 1 4 377 11 -2000ns[-2000ns]
322ms is a huge offset and I wonder if anybody has an idea of what could
be the root source.
ntp-clock-1 and ntp-clock-2 are two proper grandmasters.
ntp-clock-2 is geographically far.
ntp-clock-1 is in the same location.
PHC0 is a clock on an Intel card running under igb driver.
The PTP port of the card is connected to a PTP-enabled Cisco Nexus
switch, which is connected to a PTP grandmaster. The same grandmaster in
fact, which is also a NTP source ntp-clock-1.
I would understand 36 secons of a difference (TIA vs GMT) or some
microseconds of a difference (some network and PCIE jitter). But a third
of a second is very strange.
Do you have any ideas?
By the way, for synchronization of on-the-NIC PTP clock I tried using
ptp4l in both software and hardware mode and that did not make any
With kind regards,
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